. >>> convicted killer, jodi arias, back in a phoenix prison this morning. she was on suicide watch. >> the jury will begin deliberating tomorrow whether she should be sentenced to death. in the meantime, a rare look at arias before her sentence. >> reporter: abc's "20/20" shot this interview with the notoriously vain femme fatal, arrested in 2008, just after she flashed this smile in her mug shot. jodi arias as smug and confident as ever. >> all of the evidence to me is very compelling. but none of it proves that i committed a murder. >> reporter: we now know her confidence was sadly misplaced. >> first-degree murder, guilty. >> reporter: last week an arizona jury found her guilty of premeditated murder of her ex-boyfriend, travis alexander, whom back then she spoke of in glowing terms. >> travis was well loved and known. by a lot of people. >> reporter: she insists alexander abused her and she was forced to shoot and repeatedly stab him in self-defense. but back in 2008 she was still insisting she knew nothing about what happened to her ex. >> one day i wi